Image sensors including color adjustment path

ABSTRACT

An image sensor includes a transfer transistor including a vertical gate portion extending in a depth direction of a substrate in an active region of the substrate and photodiode regions located at positions of different depths with respect to a top surface of the substrate in the active region. At least one color adjustment path extends between at least two photodiode regions of the photodiode regions and provides a charge movement path between the at least two photodiode regions.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2012-0003082, filed on Jan. 10, 2012, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

Various embodiments described herein relate to an image sensor thatconverts an optical image into an electrical signal, and moreparticularly, to an image sensor including unit pixels, each unit pixelhaving a plurality of photodiode regions.

Due to an increase of a pixel density of an image sensor, a pixel sizemay decrease. Unit pixels of the image sensor include photodiodes thatare photoelectric conversion devices. A horizontal area of a photodiodemay decrease due to high integration of a complementarymetal-oxide-semiconductor (CMOS) image sensor, so that a full wellcapacity (FWC), which is a capacity of the photodiode that receivescharges, may also decrease. In the photodiode with decreased FWC, theFWC may vary in each red (R), green (G), and blue (B) color, which maymake it difficult to obtain a desired sensitivity and color quality.

SUMMARY

According to various embodiments described herein, there is provided animage sensor including a device isolation region defining an activeregion in a unit pixel of a substrate; a transfer transistor including avertical gate portion extending from a top surface of the substrate in adepth direction of the substrate in the active region, and a channelregion vertically extending along sidewalls of the vertical gate portionin the active region. A plurality of photodiode regions are located atpositions of different depths with respect to the top surface of thesubstrate in the active region. At least one color adjustment path areais located at a position spaced apart from the channel region. The atleast one color adjustment path area extends between at least twophotodiode regions of the plurality of photodiode regions, and providesa charge movement path, such as an electron movement path, between theat least two photodiode regions.

According to other embodiments described herein, there is provided animage sensor including a substrate including a top surface, a bottomsurface, an active region and a transfer transistor including a verticalgate portion extending from the top surface of the substrate in a depthdirection of the substrate in the active region. A plurality ofphotodiode regions are located at positions of different depths withrespect to the top surface of the substrate in the active region. Atleast one color adjustment path area is located at a position spacedapart from the vertical gate portion in the active region. The at leastone, color adjustment path area extends between at least two photodioderegions of the plurality of photodiode regions, and provides a chargemovement path, such as an electron movement path, between the at leasttwo photodiode regions. A color filter is provided on the substrate anda micro-lens is provided on the color filter.

The image sensor may include a backside illumination type image sensor.

According to various other embodiments described herein, an image sensorcomprises a semiconductor substrate including a face, and a plurality ofsemiconductor photodiodes in the semiconductor substrate, at differentdepths from the face, and being configured to absorb light of differentcolors. A semiconductor color adjustment path in the semiconductorsubstrate extends between at least two of the semiconductor photodiodesthat are different depths from the face. The semiconductor coloradjustment path may extend between the at least two of the semiconductorphotodiodes at central portions thereof, so as to be surrounded by theat least two of the semiconductor photodiodes, and/or at peripheralportions thereof, so as to be only partially surrounded by at least twoof the semiconductor photodiodes. The image sensor may also include atransfer transistor that extends into the semiconductor substrate fromthe face, wherein the semiconductor color adjustment path extendsbetween the at least two of the semiconductor photodiodes at peripheralportions thereof that are furthest away from the transfer transistor.Moreover, a respective semiconductor photodiode may include regions offirst and second different conductivity types that define asemiconductor junction therebetween that extends generally parallel tothe face, and the semiconductor color adjustment path may comprise apillar of the first conductivity type that extends into the regions offirst conductivity type of the semiconductor photodiodes.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments of the inventive concepts will be more clearlyunderstood from the following detailed description taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a diagram illustrating a configuration of an image sensoraccording to an embodiment of the inventive concepts;

FIG. 2 is an equivalent circuit diagram of a unit pixel of the imagesensor of FIG. 1;

FIG. 3A illustrates a layout of a unit pixel of the image sensor of FIG.1;

FIG. 3B is a cross-sectional view of the unit pixel of FIG. 3A, takenalong a line 3B-3B;

FIG. 3C is a cross-sectional view of an image sensor that is amodification of the image sensor of FIG. 3B, according to anotherembodiment of the inventive concepts;

FIGS. 4A through 4I are cross-sectional views that are sequentialprocesses of a method of manufacturing the image sensor, according to anembodiment of the inventive concepts;

FIG. 5A is a layout of a unit pixel of an image sensor according toanother embodiment of the inventive concepts;

FIG. 5B is a cross-sectional view of the unit pixel of FIG. 5A, takenalong a line 5B-5B′;

FIG. 6A is a layout of a unit pixel of an image sensor according toanother embodiment of the inventive concepts;

FIG. 6B is a cross-sectional view of the unit pixel of FIG. 6A, takenalong a line 6B-6B′;

FIG. 6C is a cross-sectional view of the unit pixel of FIG. 6A, takenalong a line 6C-6C′;

FIG. 7 is a cross-sectional view of a unit pixel of an image sensoraccording to another embodiment of the inventive concepts;

FIG. 8 is a cross-sectional view of a unit pixel of an image sensoraccording to another embodiment of the inventive concepts;

FIG. 9A is a layout of a unit pixel of an image sensor according toanother embodiment of the inventive concepts;

FIG. 9B is a cross-sectional view of the unit pixel of FIG. 9A, takenalong a line 9B-9B′;

FIG. 9C is a cross-sectional view of the unit pixel of FIG. 9A, takenalong a line 9C-9C′;

FIG. 10 is a cross-sectional view of an image sensor that is a backsideillumination type image sensor according to another embodiment of theinventive concepts; and

FIG. 11 is a block diagram of an imaging system including an imagesensor, according to an embodiment of the inventive concepts.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The attached drawings for illustrating example embodiments of theinventive concepts are referred to in order to gain a sufficientunderstanding of the inventive concepts, the merits thereof, and theobjectives accomplished by the implementation of the inventive concepts.

Hereinafter, the inventive concepts will be described in detail byexplaining exemplary embodiments of the inventive concept with referenceto the attached drawings. Like reference numerals in the drawings denotelike elements, and thus, repeated descriptions thereof are omitted.

The inventive concepts may, however, be embodied in many different formsand should not be construed as being limited to the embodiments setforth herein; rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey theinventive concepts to those of ordinary skill in the art.

While terms “first” and “second” are used to describe variouscomponents, it is obvious that the components are not limited to theterms “first” and “second”. The terms “first” and “second” are used onlyto distinguish between each component. For example, a first componentmay indicate a second component or a second component may indicate afirst component without conflicting with the inventive concept.

Spatially relative terms, such as “beneath,” “below,” “bottom,” “above,”“top” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

Unless expressly described otherwise, all terms including descriptive ortechnical terms which are used herein should be construed as havingmeanings that are obvious to one of ordinary skill in the art. Also,terms that are defined in a general dictionary and that are used in thefollowing description should be construed as having meanings that areequivalent to meanings used in the related description, and unlessexpressly described otherwise herein, the terms should not be construedas being ideal or excessively formal.

Also, it should also be noted that in some alternative implementations,the steps of all methods described herein may occur out of the order.For example, two steps illustrated in succession may in fact be executedsubstantially concurrently or the two steps may sometimes be executed inthe reverse order.

With respect to the drawings, shapes in the drawings may be revisedaccording to a manufacturing technology and/or a tolerance. Therefore,the attached drawings for illustrating exemplary embodiments of theinventive concepts are referred to in order to gain a sufficientunderstanding of the inventive concept, the merits thereof, and theobjectives accomplished by the implementation of the inventive concepts.

Expressions such as “at least one of,” when preceding a list ofelements, modify the entire list of elements and do not modify theindividual elements of the list. Moreover, as used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed elements and may be abbreviated herein as “/”.

FIG. 1 is a diagram illustrating a configuration of an image sensor 10according to an embodiment of the inventive concepts. FIG. 1 illustratesa configuration of a complementary metal-oxide-semiconductor (CMOS)image sensor (hereinafter, referred to as ‘CIS’).

Referring to FIG. 1, the image sensor 10 includes a pixel array region20 and CMOS control circuits 30 that are in/on a circuit substrate. Thepixel array region 20 includes a plurality of unit pixels 22 that arearrayed in a matrix. The CMOS control circuit 30 disposed around thepixel array region 20 has a plurality of CMOS transistors (not shown),provides a constant signal to the unit pixels 22 of the pixel arrayregion 20, or controls an output signal.

A structure of the unit pixel 22 varies according to elements that formthe unit pixel 22. In other embodiments, the unit pixel 22 may have astructure including 1 through 5 transistors.

FIG. 2 is an equivalent circuit diagram of the unit pixel 22.

Referring to FIG. 2, the unit pixel 22 includes a photodiode PD thatreceives light, generates photocharges due to photoelectric conversion,and accumulates the charges; a transfer transistor Tx that transfers thecharges generated by the photodiode PD to a floating diffusion regionFD; a reset transistor Rx that regularly resets the charges stored inthe floating diffusion region FD; a drive transistor Dx that functionsas a source follower buffer amplifier and buffers a signal in responseto the charges stored in the floating diffusion region FD; and a selecttransistor Sx that performs switching and addressing so as to select theunit pixel 22. In FIG. 2, “RS” indicates a signal applied to a gate ofthe reset transistor Rx, “TG” is a signal applied to a gate of thetransfer transistor Tx, and “SEL” indicates a signal applied to a gateof the select transistor Sx.

FIG. 2 illustrates circuit configuration of a unit pixel comprising onephotodiode PD and four MOS transistors, namely, the transfer transistorTx, the reset transistor Rx, the drive transistor Dx, and the selecttransistor Sx. However, one or more embodiments of the inventiveconcepts are not limited thereto.

FIGS. 3A and 3B are diagrams of an image sensor 100 according to anotherembodiment of the inventive concepts. In more detail, FIG. 3Aillustrates a layout of a unit pixel 104 of the image sensor 100, andFIG. 3B is a cross-sectional view of the unit pixel 104 of FIG. 3A,taken along a line 3B-3B′. In FIGS. 3A and 3B, like or similar membersas those of FIGS. 1 and 2 have like reference numerals, and thus,repeated descriptions thereof are omitted.

Referring to FIGS. 3A and 3B, in the unit pixel 104, a device isolationregion 108 defines an active region 106 in a substrate 102. The deviceisolation region 108 is located in a trench 102C in the substrate 102.

In other embodiments, the substrate 102 is a P-type semiconductorsubstrate. For example, the substrate 102 may comprise a P-type siliconsubstrate. A deep well 110 is provided in the substrate 102. In otherembodiments, the deep well 110 is a P-type well. A doping density in thedeep well 110 is higher than a doping density in the substrate 102.

The unit pixel 104 may be separated from another unit pixel 104 by thedevice isolation region 108 in the substrate 102. The device isolationregion 108 comprises an insulating material. An impurity region 112 thatsurrounds a sidewall and a bottom surface of the device isolation region108 is located above the substrate 102. In other embodiments, theimpurity region 112 is a P-type well. A doping density in the impurityregion 112 is higher than a doping density in the substrate 102. Theimpurity region 112 may reduce or prevent cross-talk.

In the active region 106, a recess region 102R is provided in thesubstrate 102. Also, a transfer transistor Tx is provided around therecess region 102R. A gate electrode 120 of the transfer transistor Txincludes a vertical gate portion 120V that extends from a top surface102T of the substrate 102 along a depth direction of the substrate 102,and a horizontal gate portion 120H that extends from a top portion ofthe vertical gate portion 120V along the top surface 102T of thesubstrate 102. The vertical gate portion 120V is provided in the recessregion 102R. A top surface of the horizontal gate portion 120H iscovered with an insulating capping layer 122, and sidewalls of thehorizontal gate portion 120H are covered with insulating spacers 124.

A gate insulating layer 126 is provided between the gate electrode 120and the substrate 102. A channel impurity region 128 is provided aroundthe recess region 102R of the substrate 102. The channel impurity region128 is located to surround the vertical gate portion 120V with the gateinsulating layer 126 interposed therebetween. In other embodiments, athreshold voltage of the transfer transistor Tx is adjusted due to thechannel impurity region 128. In other embodiments, the channel impurityregion 128 is provided as a P-type impurity region having a higherdoping density than that of the substrate 102.

The transfer transistor Tx includes a first channel region CH1 thatvertically extends along sidewalls of the vertical gate portion 120V inthe active region 106, a second channel region CH2 that is around abottom surface of the vertical gate portion 120V, and a third channelregion CH3 that is around a bottom surface of the horizontal gateportion 120H.

lathe active region 106, a hole accumulation device (HAD) region 130 isprovided at one side of the transfer transistor Tx and has apredetermined thickness from the top surface 102T of the substrate 102along the depth direction of the substrate 102. The HAD region 130 maycomprise a p+ type semiconductor region.

A photodiode PD may be provided in the active region 106. The photodiodePD includes a first photodiode region PD1 and a second photodiode regionPD2 that are respectively provided at positions of different depths withrespect to the top surface 102T of the substrate 102. Thus, a respectivesemiconductor photodiode PD1, PD2 includes regions of first and seconddifferent conductivity types that define a semiconductor junction (i.e.,a P-N junction) therebetween that extends generally parallel to the topface 102T. The first photodiode region PD1 and the second photodioderegion PD2 vertically overlap with each other.

The substrate 102 has different light-absorption characteristicsaccording to its depth direction. Thus, in order to accumulate chargessuch as electrons by photoelectrically converting light that is incidentfrom an external source at various wavelengths, the first photodioderegion PD1 and the second photodiode region PD2 above the substrate 102may have different depths according to lengths of the wavelengths of theincident light.

FIG. 3B illustrates an example in which the photodiode PD consists oftwo photodiode regions, i.e., the first photodiode region PD1 and thesecond photodiode region PD2. However, one or more embodiments of theinventive concepts are not limited thereto and thus at least threephotodiode regions that vertically overlap with each other may providethe photodiode PD.

The photodiode PD includes a first semiconductor region 132 having afirst conductivity type, and a plurality of second semiconductor regions142 and 144 that have a second conductivity type different from thefirst conductivity type and that are separated from each other with thefirst semiconductor region 132 interposed therebetween. The firstsemiconductor region 132 comprises a P-type impurity region, and thesecond semiconductor regions 142 and 144 comprise an N-type impurityregion. The first photodiode region PD1 includes a junction of thesecond semiconductor region 142 and the HAD region 130. The secondphotodiode region PD2 includes a junction of the second semiconductorregion 144 and the first semiconductor region 132.

The image sensor 100 includes a color adjustment path area 150. Thecolor adjustment path area 150 provides a charge movement path, such asan electron movement path, between the first photodiode region PD1 andthe second photodiode region PD2. The color adjustment path area 150 isembodied as a semiconductor area having the same conductivity type asthe second semiconductor regions 142 and 144.

The color adjustment path area 150 is located at a position distant fromsurfaces of the substrate 102, e.g., surfaces of the substrate 102 inthe recess region 102R and surfaces of the substrate 102 in the trench102C. A defect may exist on the surfaces of the substrate 102 in therecess region 102R and the trench 102C due to a damage of the substrate102, wherein the surfaces are exposed to an etch environment. If adefect exists in the color adjustment path area 150, an error may occurin a charge transfer or a dark current may be generated, and thus, thecolor adjustment path area 150 is formed in a position distant from thesurfaces of the substrate 102 in the recess region 102R and the trench102C.

The color adjustment path area 150 is separated from the transfertransistor Tx with a portion of the photodiode PD interposedtherebetween. The color adjustment path area 150 is located at aposition distant from the first through third channel regions CH1, CH2,and CH3 of the transfer transistor Tx, while the color adjustment patharea 150 extends between the first photodiode region PD1 and the secondphotodiode region PD2. Also, the color adjustment path area 150 islocated at a position distant from the device isolation region 108 andthe impurity region 112 that surrounds the device isolation region 108.

The color adjustment path area 150 is located in the substrate 102 at aposition that does not vertically overlap with the horizontal gateportion 120H of the gate electrode 120, but is not limited thereto. Inother embodiments, the horizontal gate portion 120H of the gateelectrode 120, which is above the top surface 102T of the substrate 102,may further extend toward a position of the photodiode PD. Also, atleast a portion of the color adjustment path area 150 may verticallyoverlap with the horizontal gate portion 120H of the gate electrode 120.

The color adjustment path area 150 is located at a position spaced apartfrom a vertical-direction edge PD_E (refer to FIG. 3A) of the photodiodePD toward an inner direction of the photodiode PD. Thus, sidewalls ofthe color adjustment path area 150 are surrounded by the photodiode PD.

In some embodiments, the color adjustment path area 150 has a pillarshape that extends from the second semiconductor region 142, which isrelatively close to the top surface 102T of the substrate 102, to thesecond semiconductor region 144, which is relatively close to the bottomsurface 102B of the substrate 102, while penetrating through the firstsemiconductor region 132.

In some embodiments, the color adjustment path area 150 completelypenetrates through the first semiconductor region 132 in a verticaldirection and partially penetrates into the second semiconductor regions142 and 144 in the vertical direction. In other embodiments, the coloradjustment path area 150 may completely penetrate through the firstsemiconductor region 132, and the second semiconductor regions 142 and144.

The color adjustment path area 150 extends from a position, whichpartially and horizontally overlaps with the vertical gate portion 120V,in a parallel direction to a vertical direction with respect to thevertical gate portion 120V. The color adjustment path area 150 has anapproximately straight pillar shape but a shape of the color adjustmentpath area 150 is not limited thereto. In other embodiments, the coloradjustment path area 150 may have a shape different from a straightpillar shape.

When signal charges are accumulated in the photodiode PD, the coloradjustment path area 150 is used as a charge movement path, such as anelectron movement path, by which a charge amount that exceeds a fullwell capacity (FWC) of one of the first photodiode region PD1 and thesecond photodiode region PD2 flows to the other one of the firstphotodiode region PD1 and the second photodiode region PD2. Thus,electrons of light having different wavelengths may be accumulated inthe photodiode PD having an increased FWC due to the color adjustmentpath area 150, without the need for a spatial limitation of the firstphotodiode region PD1 and the second photodiode region PD2. By using thecolor adjustment path area 150, without the need for the spatiallimitation of the first photodiode region PD1 and the second photodioderegion PD2, an FWC for each of the electrons obtained from light havingdifferent wavelengths corresponding to different colors may be variablyadjusted in various operation environments of the image sensor 100.

In the active region 106, a floating diffusion region 160 having apredetermined thickness extending from the top surface 102T of thesubstrate 102 in a depth direction of the substrate 102 is located on aside of the transfer transistor Tx, which is opposite to the side wherethe photodiode PD is located.

Light that is incident to the photodiode PD on the top surface 102T orthe bottom surface 102B of the substrate 102 is photoelectricallyconverted in the first photodiode region PD1 and the second photodioderegion PD2, so that signal charges are generated. The generated signalcharges are accumulated in the second semiconductor region 142 formingthe first photodiode region PD1 or in the second semiconductor region144 forming the second photodiode region PD2. When a FWC of one of thesecond semiconductor regions 142 and 144 is exceeded, charges thatexceed the FWC may flow to the other one of the second semiconductorregions 142 and 144 via the color adjustment path area 150.

According to a voltage that is applied to the gate electrode 120 of thetransfer transistor Tx, a potential of the first through third channelregions CH1, CH2, and CH3 of the transfer transistor Tx may be changed.When a predetermined voltage is applied to the gate electrode 120 of thetransfer transistor Tx after signal charges are accumulated in thesecond semiconductor regions 142 and 144, signal charges in the secondsemiconductor regions 142 and 144 and the color adjustment path area 150may be transmitted to the floating diffusion region 160 via the firstthrough third channel regions CH1, CH2, and CH3.

The image sensor 100 includes the first photodiode region PD1 and thesecond photodiode region PD2 that vertically overlap with each otheralong the depth direction of the substrate 102, and the color adjustmentpath area 150 that provides an electron movement path between the firstphotodiode region PD1 and the second photodiode region PD2, so that theimage sensor 100 may increase an FWC in the first photodiode region PD1and the second photodiode region PD2. Thus, although a size of a unitpixel of the image sensor 100 becomes minute, an FWC in the photodiodePD may be increased and excellent sensitivity and color quality may beachieved.

FIG. 3C is a cross-sectional view of an image sensor 100A that is amodification of the image sensor 100 of FIG. 3B, according to anotherembodiment of the inventive concepts. In FIG. 3C, like members as thoseof FIG. 3B have like reference numerals, and thus, repeated descriptionsthereof are omitted here.

Referring to FIG. 3C, the image sensor 100A includes a color adjustmentpath area 150A. A detailed structure of the color adjustment path area150A is the same as a structure of the color adjustment path area 150described with reference to FIG. 3B. However, in FIG. 3C the coloradjustment path area 150A completely penetrates through the secondsemiconductor region 144 in a vertical direction. In other embodiments,the color adjustment path area 150A may be formed to completelypenetrate through the second semiconductor region 142.

FIGS. 4A through 4I are cross-sectional views that are sequentialprocesses of a method of manufacturing the image sensor 100, accordingto an embodiment of the inventive concepts. In FIGS. 4A through 4I, likeor similar members as those of FIGS. 1, 2, 3A, and 3B have likereference numerals, and thus, repeated descriptions thereof are omitted.

Referring to FIG. 4A, a P-type substrate 102 is arranged. A P+ type deepwell 110 is formed in the substrate 102. After a trench 102C is formedin the substrate 102, impurity ions are injected to the substrate 102via an inner wall of the trench 102C, so that a P+ type impurity region112 is formed around the trench 102C. Afterward, a device isolationregion 108 is formed in the trench 102C, thereby defining an activeregion 106 in the substrate 102.

A first mask 412 is formed above the substrate 102. In one or moreembodiments, the first mask 412 is formed of a photoresist layer.Afterward, impurity ions are injected to the active region 106 of thesubstrate 102 by using the first mask 412 as an ion injection mask, sothat a P-type first semiconductor region 132 is formed.

Referring to FIG. 4B, after the first mask 412 that is used in theprocess of FIG. 4A is removed, a second mask 414 is formed above thesubstrate 102. In one or more embodiments, the second mask 414 is formedof a photoresist layer. By using the second mask 414 as an ion injectionmask, impurity ions are injected to the active region 106 of thesubstrate 102, so that an N-type second semiconductor region 142 isformed on the first semiconductor region 132.

Referring to FIG. 4C, after the second mask 414 that is used in theprocess of FIG. 4B is removed, a third mask 416 is formed above thesubstrate 102. In one or more embodiments, the third mask 416 is formedof a photoresist layer. By using the third mask 416 as an ion injectionmask, impurity ions are injected to the active region 106 of thesubstrate 102, so that an N-type second semiconductor region 144 havingan interface with the first semiconductor region 132 at a lower side ofthe first semiconductor region 132 is formed. In other embodiments, asingle mask may be used to form two or more of the semiconductor regions142, 132 and/or 144.

In the present embodiment, the second semiconductor region 142 that ishigher than the second semiconductor region 144 is first formed and thenthe second semiconductor region 144 that is lower than the secondsemiconductor region 142 is formed. However, a forming order is notlimited thereto. That is, in other embodiments, the second semiconductorregion 144 may be first formed according to the process of FIG. 4C, andthen the second semiconductor region 142 may be formed according to theprocess of FIG. 4B.

Referring to FIG. 4D, after the third mask 416 that is used in theprocess of FIG. 4C is removed, a fourth mask 418 is formed above thesubstrate 102. In one or more embodiments, the fourth mask 418 is formedof a photoresist layer. By using the fourth mask 418 as an ion injectionmask, impurity ions are injected to the active region 106 of thesubstrate 102, so that an N-type color adjustment path area 150 that isconnected between the second semiconductor regions 142 and 144 andpenetrates through the first semiconductor region 132 is formed.

Referring to FIG. 4E, after the fourth mask 418 that is used in theprocess of FIG. 4D is removed, a fifth mask 420 is formed above thesubstrate 102. In one or more embodiments, the fifth mask 420 is formedof a photoresist layer. By using the fifth mask 420 as an ion injectionmask, impurity ions are injected to the active region 106 of thesubstrate 102, so that a P+ type HAD region 130 that extends from a topsurface 102T of the substrate 102 to a top surface of the secondsemiconductor region 142 in a depth direction of the substrate 102 isformed. The P+ type HAD region 130 is formed to have an interface withthe top surface of the second semiconductor region 142. As a result, aphotodiode PD, including a first photodiode region PD1 and a secondphotodiode region PD2, is formed. In other embodiments, a single maskmay be used to form two or more of the semiconductor regions 130, 142,132 and/or 144.

Referring to FIG. 4F, after the fifth mask 420 that is used in theprocess of FIG. 4E is removed, a channel impurity region 128 is formedby injecting impurity ions to a region in which a transfer transistor Txis to be formed. The channel impurity region 128 may be doped with aP-type impurity. Afterward, a portion of the substrate 102 is etched sothat a recess region 102R is formed.

In one or more embodiments, in order to form the recess region 102R tohave rounded upper and lower corners, before the recess region 102R isformed, a trench for a gate (not shown) may be formed by etching aportion of the substrate 102 in the channel impurity region 128, athermal oxide layer (not shown) may be formed on a sidewall and a bottomsurface of the trench for a gate by performing a thermal oxidationprocess, and then the thermal oxide layer may be removed via a wetetching process. As a result, as illustrated in FIG. 4F, the recessregion 102R may be formed having rounded upper and lower corners.

Referring to FIG. 4G, a gate insulating layer 126 is formed above thesubstrate 102, and a conductive layer 120L for forming a gate electrode120 is formed on the gate insulating layer 126.

The gate insulating layer 126 is conformally formed above the substrate102 along profiles of a sidewall and a bottom surface of the recessregion 102R.

The conductive layer 120L is formed to fill an inside of the recessregion 102R. The conductive layer 120L may be formed of dopedpolysilicon, metal, metal nitride, and/or metal silicide.

Referring to FIG. 4H, an insulating capping layer 122 is formed on theconductive layer 120L, and a portion of the conductive layer 120L isetched by using the insulating capping layer 122 as an etch mask, sothat the gate electrode 120, including a vertical gate portion 120V anda horizontal gate portion 120H, is formed. Afterward, insulating spacers124 that cover sidewalls of the gate electrode 120 are formed.

Referring to FIG. 4I, after a sixth mask (not shown) that covers thesubstrate 102 in a direction above the gate electrode 120 and thephotodiode PD is formed, impurity ions are injected to the active region106 of the substrate 102 by using the sixth mask as an ion injectionmask, so that a floating diffusion region 160 having a predeterminedthickness extending from the top surface 102T of the substrate 102 inthe depth direction of the substrate 102 is formed. Afterward, the sixthmask is removed.

FIGS. 5A and 5B are diagrams illustrating an image sensor 200 accordingto another embodiment of the inventive concepts. In more detail, FIG. 5Ais a layout of a unit pixel 204 of the image sensor 200, and FIG. 5B isa cross-sectional view of the unit pixel 204 of FIG. 5A, taken along aline 5B-5B′. The unit pixel 204 may be one of the unit pixels 22 ofFIG. 1. In FIGS. 5A and 5B, like or similar members as those of FIGS. 1,2, 3A, and 3B have like reference numerals, and thus, repeateddescriptions thereof are omitted.

Referring to FIGS. 5A and 5B, the image sensor 200 includes a coloradjustment path area 250. The color adjustment path area 250 provides acharge movement path, such as an electron movement path, between a firstphotodiode region PD1 and a second photodiode region PD2. The coloradjustment path area 250 comprises a semiconductor area having the sameconductivity type as second semiconductor regions 142 and 144 of aphotodiode PD.

The color adjustment path area 250 is located at a position distant fromsurfaces of a substrate 102, e.g., surfaces of the substrate 102 in arecess region 102R and surfaces of the substrate 102 in a trench 102C.

The color adjustment path area 250 is located at a position thatcontacts a horizontal-direction edge PD_E (refer to FIG. 5A) of thephotodiode PD, and is partially surrounded by the photodiode PD. Thecolor adjustment path area 250 contacts an edge portion of the edgePD_E, wherein the edge is positioned farthest from a vertical gateportion 120V.

The color adjustment path area 250 is spaced apart from a deviceisolation region 108, and a portion of the color adjustment path area250 contacts an impurity region 112 that surrounds the device isolationregion 108. In other embodiments, the color adjustment path area 250 maybe located at a position that is near the horizontal-direction edge PD_Eof the photodiode PD and that does not contact the impurity region 112.

The color adjustment path area 250 is spaced apart from a transfertransistor Tx with the photodiode PD interposed therebetween. The coloradjustment path area 250 vertically extends between the first photodioderegion PD1 and the second photodiode region PD2.

The color adjustment path area 250 contacts each of the firstsemiconductor region 132 and the second semiconductor regions 142 and144 at horizontal-direction edges of the first semiconductor region 132and the second semiconductor regions 142 and 144. A portion of the coloradjustment path area 250 extends from a position, which partially andhorizontally overlaps with the vertical gate portion 120V, in a paralleldirection to a vertical direction with respect to the vertical gateportion 120V. In FIG. 5B, the color adjustment path area 250 has anapproximately straight pillar shape but a shape of the color adjustmentpath area 250 is not limited thereto. In other embodiments, the coloradjustment path area 250 may have a shape different from a straightpillar shape.

When signal charges are accumulated in the photodiode PD, the coloradjustment path area 250 is used as a charge movement path, such as anelectron movement path, by which a charge amount that exceeds a FWC ofone of the first photodiode region PD1 and the second photodiode regionPD2 flows to the other one of the first photodiode region PD1 and thesecond photodiode region PD2.

Light that is incident to the photodiode PD on the top surface 102T or abottom surface 102B of the substrate 102 is photoelectrically convertedin the first photodiode region PD1 and the second photodiode region PD2,so that signal charges are generated. The generated signal charges areaccumulated in the second semiconductor region 142 forming the firstphotodiode region PD1 or in the second semiconductor region 144 formingthe second photodiode region PD2. When a FWC of one of the secondsemiconductor regions 142 and 144 is exceeded, charges that exceed theFWC may flow to the other one of the second semiconductor regions 142and 144 via the color adjustment path area 250. After the signal chargesare accumulated in the second semiconductor regions 142 and 144, when apredetermined voltage is applied to a gate electrode 120 of the transfertransistor Tx, the signal charges in the second semiconductor regions142 and 144 and the color adjustment path area 250 may be transmitted toa floating diffusion region 160 via first through third channel regionsCH1, CH2, and CH3.

The image sensor 200 includes the first photodiode region PD1 and thesecond photodiode region PD2 that vertically overlap with each otheralong the depth direction of the substrate 102, and the color adjustmentpath area 250 that provides an electron movement path between the firstphotodiode region PD1 and the second photodiode region PD2, so that theimage sensor 200 may increase an FWC in the first photodiode region PD1and the second photodiode region PD2. Thus, although a size of a unitpixel of the image sensor 200 becomes minute, an FWC in the photodiodePD may be increased and excellent sensitivity and color quality may beachieved.

FIGS. 6A through 6C are diagrams illustrating an image sensor 300according to another embodiment of the inventive concepts. In moredetail, FIG. 6A is a layout of a unit pixel 304 of the image sensor 300,FIG. 6B is a cross-sectional view of the unit pixel 304 of FIG. 6A,taken along a line 6B-6B′, and FIG. 6C is a cross-sectional view of theunit pixel 304 of FIG. 6A, taken along a line 6C-6C′. The unit pixel 304may be one of the unit pixels 22 of FIG. 1. In FIGS. 6A through 6C, likeor similar members as those of FIGS. 1, 2, 3A, and 3B have likereference numerals, and thus, repeated descriptions thereof are omitted.

Referring to FIGS. 6A through 6C, the image sensor 300 includes aplurality of color adjustment path areas 350. For example, the coloradjustment path areas 350 include a first color adjustment path area350A and a second color adjustment path area 350B that are spaced aparteach other by a predetermined distance.

Each of the first color adjustment path area 350A and the second coloradjustment path area 350B provides a charge movement path, such as anelectron movement path, between a first photodiode region PD1 and asecond photodiode region PD2. The first color adjustment path area 350Aand the second color adjustment path area 350B comprise semiconductorareas having the same conductivity type as second semiconductor regions142 and 144 of a photodiode PD.

Each of the first color adjustment path area 350A and the second coloradjustment path area 350B is located at a position distant from surfacesof a substrate 102, e.g., surfaces of the substrate 102 in a recessregion 102R and surfaces of the substrate 102 in a trench 102C.

Each of the first color adjustment path area 350A and the second coloradjustment path area 350B is located at the position that contacts ahorizontal-direction edge PD_E of the photodiode PD, and is partiallysurrounded by the photodiode PD.

A portion of each of the first color adjustment path area 350A and aportion of the second color adjustment path area 350B contact animpurity region 112. In other embodiments, at least one of the firstcolor adjustment path area 350A and the second color adjustment patharea 350B may be located at a position that contacts thehorizontal-direction edge PD_E of the photodiode PD and that does notcontact the impurity region 112.

Each of the first color adjustment path area 350A and the second coloradjustment path area 350B is spaced apart from a transfer transistor Txwith the photodiode PD interposed therebetween. Each of the first coloradjustment path area 350A and the second color adjustment path area 350Bvertically extends between the first photodiode region PD1 and thesecond photodiode region PD2.

Each of the first color adjustment path area 350A and the second coloradjustment path area 350B contacts the first semiconductor region 132and the second semiconductor regions 142 and 144 at horizontal-directionedges of the first semiconductor region 132 and the second semiconductorregions 142 and 144. Each of the first color adjustment path area 350Aand the second color adjustment path area 350B has a straight pillarshape extending from a position, which partially and horizontallyoverlaps with the vertical gate portion 120V, in a parallel direction toa vertical direction with respect to the vertical gate portion 120V. InFIG. 6C, each of the first color adjustment path area 350A and thesecond color adjustment path area 350B has a straight pillar shape butshapes of the first color adjustment path area 350A and the second coloradjustment path area 350B are not limited thereto. In other embodiments,the first color adjustment path area 350A and the second coloradjustment path area 350B may have a shape different from a straightpillar shape.

FIG. 6C illustrates an example in which the first color adjustment patharea 350A and the second color adjustment path area 350B have the samedepth and are at the same levels. However, in other embodiments, thefirst color adjustment path area 350A and the second color adjustmentpath area 350B may be formed at different levels. Also, in otherembodiments, the first color adjustment path area 350A and the secondcolor adjustment path area 350B may have different depths in a depthdirection of the substrate 102.

When signal charges are accumulated in the photodiode PD, each of thefirst color adjustment path area 350A and the second color adjustmentpath area 350B is used as a charge movement path, such as an electronmovement path, by which a charge amount that exceeds a FWC of one of thefirst photodiode region PD1 and the second photodiode region PD2 flowsto the other one of the first photodiode region PD1 and the secondphotodiode region PD2.

Light that is incident to the photodiode PD on the top surface 102T or abottom surface 102B of the substrate 102 is photoelectrically convertedin the first photodiode region PD1 and the second photodiode region PD2,so that signal charges are generated. The generated signal charges areaccumulated in the second semiconductor region 142 forming the firstphotodiode region PD1 or in the second semiconductor region 144 formingthe second photodiode region PD2. When a FWC of one of the secondsemiconductor regions 142 and 144 is exceeded, charges that exceed theFWC may flow to the other one of the second semiconductor regions 142and 144 via at least one of the first color adjustment path area 350Aand the second color adjustment path area 350B. After the signal chargesare accumulated in the second semiconductor regions 142 and 144, when apredetermined voltage is applied to a gate electrode 120 of the transfertransistor Tx, the signal charges in the second semiconductor regions142 and 144 and the first color adjustment path area 350A and the secondcolor adjustment path area 350B may be transmitted to a floatingdiffusion region 160 via first through third channel regions CH1, CH2,and CH3.

The image sensor 300 includes the first photodiode region PD1 and thesecond photodiode region PD2 that vertically overlap with each otheralong the depth direction of the substrate 102, and the first coloradjustment path area 350A and the second color adjustment path area 350Bthat provide an electron movement path between the first photodioderegion PD1 and the second photodiode region PD2, so that the imagesensor 300 may increase an FWC in the first photodiode region PD1 andthe second photodiode region PD2. Thus, although a size of a unit pixelof the image sensor 300 becomes minute, an FWC in the photodiode PD maybe increased and excellent sensitivity and color quality may beachieved.

FIG. 7 is a cross-sectional view of a unit pixel 404 of an image sensor400 according to another embodiment of the inventive concepts. The unitpixel 404 may be one of the unit pixels 22 of FIG. 1. In FIG. 7, like orsimilar members as those of FIGS. 1, 2, 3A, and 3B have like referencenumerals, and thus, repeated descriptions thereof are omitted. Forexample, a member with reference numeral “4xx” in FIG. 7 indicates likeor similar member as a member with reference numeral “1xx” in FIGS. 3Aand 3B. Thus, in order to avoid redundancy, repeated descriptionsthereof are omitted here.

Referring to FIG. 7, in the unit pixel 404 of the image sensor 400, aphotodiode PD, including first, second, third, and fourth photodioderegions PD1, PD2, PD3, and PD4 that are sequentially provided from a topsurface 402T of a substrate 402 in a depth direction of the substrate402, is provided in an active region 406 of the substrate 402.

The photodiode PD includes three first semiconductor regions 432, 434,and 436 and four second semiconductor regions 442, 444, 446, and 448,which are alternately disposed one-by-one in a vertical direction. Thefirst semiconductor regions 432, 434, and 436 are formed as P-typeimpurity regions, and the second semiconductor regions 442, 444, 446,and 448 are formed as N-type impurity regions.

The first photodiode region PD1 includes an interface or junctionbetween the second semiconductor region 442 and an HAD region 430. Thesecond photodiode region PD2 includes an interface between the secondsemiconductor region 444 and the first semiconductor region 432. Thethird photodiode region PD3 includes an interface between the secondsemiconductor region 446 and the first semiconductor region 434. Thefourth photodiode region PD4 includes an interface between the secondsemiconductor region 448 and the first semiconductor region 436.

The second semiconductor region 448 that forms the fourth photodioderegion PD4 faces a bottom surface of a vertical gate portion 420V with asecond channel region CH2 interposed therebetween.

The first through fourth photodiode regions PD1, PD2, PD3, and PD4vertically overlap with each other.

A depth of each of the first through fourth photodiode regions PD1, PD2,PD3, and PD4 may correspond to a transmittance depth of each ofwavelengths of light incident to the substrate 402, i.e., the depth ofeach of the first through fourth photodiode regions PD1, PD2, PD3, andPD4 may correspond to a depth at which an intensity of light having aparticular wavelength is highest in the substrate 402. For example, in acase of a front-side illumination type image sensor in which light isincident on the top surface 402T of the substrate 402, the firstphotodiode region PD1 may be disposed to correspond to a transmittancedepth of blue (B) light having a relatively short wavelength. The secondphotodiode region PD2 may be disposed to correspond to a transmittancedepth of green (G) light. The third photodiode region PD3 may bedisposed to correspond to a transmittance depth of red (R) light. Thefourth photodiode region PD4 may be disposed to correspond to atransmittance depth of infrared rays. By disposing the first throughfourth photodiode regions PD1, PD2, PD3, and PD4 at different depths inthe substrate 402, color separation may be possible according to a depthof the substrate 402, and an image sensor for a three-dimensional (3D)image may be embodied. As another embodiment, a backside illuminationtype image sensor in which light is incident on a bottom surface 402B ofthe substrate 402 may have a similar configuration as a configuration ofthe front-side illumination type image sensor. However, in a case of thebackside illumination type image sensor, types of colors separated inthe first through fourth photodiode regions PD1, PD2, PD3, and PD4 aredetermined according to transmittance depths from the bottom surface402B of the substrate 402.

The image sensor 400 includes a color adjustment path area 450. Thecolor adjustment path area 450 provides a charge movement path, such asan electron movement path, between the first through fourth photodioderegions PD1, PD2, PD3, and PD4. The color adjustment path area 450 isprovided as a semiconductor area having the same conductivity type asthe second semiconductor regions 442, 444, 446, and 448 of thephotodiode PD.

When signal charges are accumulated in the photodiode PD, the coloradjustment path area 450 is used as an electron movement path by which acharge amount that exceeds a FWC of some of the first through fourthphotodiode regions PD1, PD2, PD3, and PD4 flows to the other firstthrough fourth photodiode regions PD1, PD2, PD3, and PD4.

A detailed configuration of the color adjustment path area 450 isreferred to by the features of the color adjustment path area 150described above with reference to FIGS. 3A and 3B.

In order to form the image sensor 400 of FIG. 7, processes that aresimilar to the processes of the method described above with reference toFIGS. 4A through 4I may be performed. However, in order to form thephotodiode PD including the first through fourth photodiode regions PD1,PD2, PD3, and PD4, the three first semiconductor regions 432, 434, and436 are sequentially formed in a similar manner to the process of FIG.4B that is related to forming the first semiconductor region 132. Ioninjection processes to form the three first semiconductor regions 432,434, and 436 may be performed by using the same ion injection mask.Alternatively, different masks may be used. Then, similarly to theprocesses of FIGS. 4B and 4C that are related to forming the secondsemiconductor regions 142 and 144, the four second semiconductor regions442, 444, 446, and 448 are sequentially formed. In one or moreembodiments, ion injection processes to form some of the four secondsemiconductor regions 442, 444, 446, and 448, e.g., the three secondsemiconductor regions 442, 444, and 446 may be performed by using thesame ion injection mask. Alternatively, different masks may be used.Afterward, similarly to the process of FIG. 4D that is related toforming the color adjustment path area 150, the color adjustment patharea 450 is formed.

FIG. 7 illustrates an example in which the color adjustment path area450 is embodied in a straight pillar shape extending from the secondsemiconductor region 442, which among the four second semiconductorregions 442, 444, 446, and 448 is closer to the top surface 402T of thesubstrate 402, to the second semiconductor region 448, which among thefour second semiconductor regions 442, 444, 446, and 448 is closer tothe bottom surface 402B of the substrate 402. However, one or moreembodiments of the inventive concepts are not limited thereto. Forexample, the color adjustment path area 450 may have one of variousshapes different from the straight pillar shape. In other embodiments,the image sensor 400 may include a plurality of color adjustment pathareas (not shown) comprising a plurality of impurity areas positioned atdifferent depths from the top surface 402T of the substrate 402, insteadof including the color adjustment path area 450.

FIG. 8 is a cross-sectional view of a unit pixel 504 of an image sensor500 according to another embodiment of the inventive concepts. The unitpixel 504 may be one of the unit pixels 22 of FIG. 1. In FIG. 8, like orsimilar members as those of FIGS. 1 through 7 have like referencenumerals, and thus, repeated descriptions thereof are omitted.

Referring to FIG. 8, the image sensor 500 includes a photodiode PDhaving first, second, third, and fourth photodiode regions PD1, PD2,PD3, and PD4 that are sequentially located from a top surface 402T of asubstrate 402 in a depth direction of the substrate 402. The imagesensor 500 includes a color adjustment path area 550. The coloradjustment path area 550 provides a charge movement path, such as anelectron movement path, between the first through fourth photodioderegions PD1, PD2, PD3, and PD4. The color adjustment path area 550 isembodied as a semiconductor area having the same conductivity type asthe second semiconductor regions 442, 444, 446, and 448 of thephotodiode PD.

When signal charges are accumulated in the photodiode PD, the coloradjustment path area 550 is used as an electron movement path by which acharge amount that exceeds a FWC of some of the first through fourthphotodiode regions PD1, PD2, PD3, and PD4 flows to other regions of thefirst through fourth photodiode regions PD1, PD2, PD3, and PD4.

A detailed configuration of the color adjustment path area 550 isreferred to by the features of the color adjustment path area 250described above with reference to FIGS. 5A and 5B.

FIG. 8 illustrates an example in which the color adjustment path area550 has an approximately straight pillar shape that contacts ahorizontal-direction edge of the photodiode PD, which is positionedfarthest from a vertical gate portion 420V, and that extends from thesecond semiconductor region 442, which among the second semiconductorregions 442, 444, 446, and 448 is closest to the top surface 402T of thesubstrate 402, to the second semiconductor region 448, which among thesecond semiconductor regions 442, 444, 446, and 448 is closest to abottom surface 402B of the substrate 402. However, one or moreembodiments of the inventive concepts are not limited thereto. Forexample, the color adjustment path area 550 may have one of variousshapes different from the straight pillar shape. In other embodiments,the image sensor 500 may include a plurality of color adjustment pathareas (not shown) provided as a plurality of impurity areas positionedat different depths from the top surface 402T of the substrate 402,instead of including the color adjustment path area 550 provided as oneimpurity area, as shown in FIG. 8.

FIGS. 9A through 9C are diagrams illustrating an image sensor 600according to another embodiment of the inventive concepts. In moredetail, FIG. 9A is a layout of a unit pixel 604 of the image sensor 600,FIG. 9B is a cross-sectional view of the unit pixel 604 of FIG. 9A,taken along a line 9B-9B′, and FIG. 9C is a cross-sectional view of theunit pixel 604 of FIG. 9A, taken along a line 9C-9C′. The unit pixel 604may be one of the unit pixels 22 of FIG. 1. In FIGS. 9A through 9C, likeor similar members as those of FIGS. 1 through 8 have like referencenumerals, and thus, repeated descriptions thereof are omitted.

Referring to FIGS. 9A through 9C, the image sensor 600 includes aphotodiode PD having first, second, third, and fourth photodiode regionsPD1, PD2, PD3, and PD4 that are sequentially provided from a top surface402T of a substrate 402 in a depth direction of the substrate 402. Also,the image sensor 600 includes a plurality of color adjustment path areas650. The color adjustment path areas 650 include a first coloradjustment path area 650A and a second color adjustment path area 650Bthat are separated from each other by a predetermined distance.

Each of the first color adjustment path area 650A and the second coloradjustment path area 650B provides a charge movement path, such as anelectron movement path, between the first through fourth photodioderegions PD1, PD2, PD3, and PD4. The first color adjustment path area650A and the second color adjustment path area 650B are embodied assemiconductor areas having the same conductivity type as secondsemiconductor regions 442, 444, 446, and 448 of the photodiode PD.

When signal charges are accumulated in the photodiode PD, each of thefirst color adjustment path area 650A and the second color adjustmentpath area 650B is used as a charge movement path, such as an electronmovement path, by which a charge amount that exceeds a FWC of some ofthe first through fourth photodiode regions PD1, PD2, PD3, and PD4 flowsto other regions of the first through fourth photodiode regions PD1,PD2, PD3, and PD4.

Detailed configurations of the first color adjustment path area 650A andthe second color adjustment path area 650B are referred to by thefeatures of the first color adjustment path area 350A and the secondcolor adjustment path area 350B described above with reference to FIGS.6A through 6C.

FIG. 10 is a cross-sectional view of an image sensor 700 that is abackside illumination type image sensor according to another embodimentof the inventive concepts. In FIG. 10, like members as those of FIG. 3Bdenote like reference numerals, and thus, repeated descriptions thereofare omitted here.

Referring to FIG. 10, the image sensor 700 includes an interlayerinsulating layer 180 that is on, and in some embodiments covers, asubstrate 102 and a transfer transistor Tx in a direction above a topsurface 102T of the substrate 102. In the interlayer insulating layer180, a plurality of wiring layers 182 are provided. The wiring layers182 may be electrically connected to a gate electrode 120 of thetransfer transistor Tx. The interlayer insulating layer 180 may beprovided as a multi-layer structure in which a plurality of insulatinglayers are stacked.

The image sensor 700 further includes a color filter 186 that is on, andin some embodiments covers, the substrate 102 in a direction below abottom surface 102B of the substrate 102, and a micro-lens 190 that ison the color filter 186. In one or more embodiments, the color filter186 may be one of R, G, and B colors. In other embodiments, at least oneof a planarization layer (not shown), a reflection prevention layer (notshown), and a passivation layer (not shown) may be further arrangedbetween the bottom surface 102B of the substrate 102 and the colorfilter 186.

FIG. 10 illustrates an example of a backside illumination type imagesensor in which light is incident from the bottom surface 102B of thesubstrate 102 to the inside of the substrate 102, but one or moreembodiments of the inventive concepts are not limited thereto. Althoughnot illustrated, in a case of a front-side illumination type imagesensor in which a color filter and a micro-lens are arranged on the topsurface 102T of the substrate 102, and light is incident from the topsurface 102T of the substrate 102 to the inside of the substrate 102,the front-side illumination type image sensor may similarly include theimage sensor 700 having a color adjustment path area 150, as shown inFIG. 10.

FIG. 10 illustrates the example of the backside illumination type imagesensor using a structure of the image sensor 700 including the coloradjustment path area 150 of FIG. 3B, but one or more embodiments of theinventive concepts are not limited thereto. In other embodiments, theimage sensor 700 may be at least one of the image sensors 100A, 200,300, 400, 500, and 600, each including at least one of the coloradjustment path areas 150A, 250, 350, 450, 550, and 650.

FIG. 11 is a block diagram of an imaging system 800 including an imagesensor, according to an embodiment of the inventive concepts.

Referring to FIG. 11, the imaging system 800 processes an output imageof a CMOS image sensor 810.

The imaging system 800 includes a processor 840 capable ofreceiving/transmitting data from/to an input/output (I/O) device 830 viaa bus 820. In one or more embodiments, the processor 840 is embodied asa microprocessor or a central processing unit (CPU). In the imagingsystem 800, the processor 840 may exchange data with a floppy disk drive(FDD) 850, a compact disk read-only memory (CD ROM) drive 860 and/oranother disk drive, a port 870, and/or a random-access memory (RAM) 880via the bus 820, and may reproduce an image with respect to data, whichis output from the CMOS image sensor 810.

The port 870 may couple a video card, a sound card, a memory card, auniversal serial bus (USB) and/or the like, and/or may perform datacommunication with another system. In one or more embodiments, the CMOSimage sensor 810 and the processor 840 may be integrated together. Insome embodiments, the CMOS image sensor 810 and the RAM 880 may beintegrated together. Alternatively, the CMOS image sensor 810 and theprocessor 840 may be separate chips.

The imaging system 800 includes at least one of the image sensors 100,100A, 200, 300, 400, 500, and 600 described above with reference toFIGS. 1 through 9C.

The imaging system 800 may be applied to various devices includingdigital cameras, camcorders, personal communication systems (PCSs), gameplayers, security cameras, medial micro-cameras, robots, or the like.

Many different embodiments have been disclosed herein, in connectionwith the above description and the drawings. It will be understood thatit would be unduly repetitious and obfuscating to literally describe andillustrate every combination and subcombination of these embodiments.Accordingly, the present specification, including the drawings, shall beconstrued to constitute a complete written description of allcombinations and subcombinations of the embodiments described herein,and of the manner and process of making and using them, and shallsupport claims to any such combination or subcombination.

While the inventive concepts have been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the following claims.

What is claimed is:
 1. An image sensor comprising: a device isolation region defining an active region in a unit pixel of a substrate; a transfer transistor comprising a vertical gate portion extending from a top surface of the substrate in a depth direction of the substrate in the active region, and a channel region vertically extending along sidewalls of the vertical gate portion in the active region; a plurality of photodiode regions located at positions of different depths with respect to the top surface of the substrate in the active region; and at least one color adjustment path area located at a position spaced apart from the channel region, the at least one color adjustment path area extending between at least two photodiode regions of the plurality of photodiode regions, and providing a charge movement path between the at least two photodiode regions.
 2. The image sensor of claim 1, wherein the at least one color adjustment path area is located at a position spaced apart from the device isolation region.
 3. The image sensor of claim 1, wherein the at least one color adjustment path area comprises a color adjustment path area that penetrates through the plurality of photodiode regions so as to be surrounded by the plurality of photodiode regions.
 4. The image sensor of claim 1, wherein the at least one color adjustment path area comprises an inner color adjustment path area located at a position spaced apart from a horizontal-direction edge of at least one of the plurality of photodiode regions, and surrounded by the plurality of photodiode regions.
 5. The image sensor of claim 1, wherein the at least one color adjustment path area comprises at least one edge-side color adjustment path area located at a position contacting a horizontal-direction edge of at least one of the plurality of photodiode regions, and partially surrounded by the plurality of photodiode regions.
 6. The image sensor of claim 5, wherein the at least one edge-side color adjustment path area contacts a portion of the horizontal-direction edge of the at least one of the plurality of photodiode regions, wherein the portion is farthest from the vertical gate portion.
 7. The image sensor of claim 5, wherein the at least one edge-side color adjustment path area comprises a plurality of color adjustment path areas that contact a plurality of portions of the horizontal-direction edge of the at least one of the plurality of photodiode regions.
 8. The image sensor of claim 1, further comprising an impurity region located in the substrate so as to surround sidewalls and a bottom surface of the device isolation region, and being in contact with a portion of the at least one color adjustment path area.
 9. The image sensor of claim 1, further comprising an impurity region located in the substrate so as to surround sidewalls and a bottom surface of the device isolation region, and being spaced apart from the at least one color adjustment path area.
 10. The image sensor of claim 1, wherein the transfer transistor further comprises a horizontal gate portion extending from a top portion of the vertical gate portion along the top surface of the substrate, and the at least one color adjustment path area is located at a position that does not vertically overlap with the horizontal gate portion in the substrate.
 11. The image sensor of claim 1, wherein the plurality of photodiode regions vertically overlap with each other.
 12. The image sensor of claim 1, wherein the plurality of photodiode regions comprise a first semiconductor region having a first conductivity type, and a plurality of second semiconductor regions having a second conductivity type different from the first conductivity type, the second semiconductor regions being spaced apart from each other with the first semiconductor region interposed therebetween, and wherein the at least one color adjustment path area comprises a third semiconductor region having the second conductivity type.
 13. The image sensor of claim 12, wherein the at least one color adjustment path area has a shape of a straight pillar extending from a top second semiconductor region of the plurality of second semiconductor regions, through the first semiconductor region to a bottom second semiconductor region of the plurality of second semiconductor regions, the top second semiconductor region being closer to the top surface of the substrate, the bottom second semiconductor region being closer to a bottom surface of the substrate.
 14. An image sensor comprising: a substrate comprising a top surface, a bottom surface, and an active region; a transfer transistor comprising a vertical gate portion extending from the top surface of the substrate in a depth direction of the substrate in the active region; a plurality of photodiode regions located at positions of different depths with respect to the top surface of the substrate in the active region; at least one color adjustment path area located at a position spaced apart from the vertical gate portion in the active region, the at least one color adjustment path area extending between at least two photodiode regions of the plurality of photodiode regions, and providing a charge movement path between the at least two photodiode regions; a color filter on the substrate; and a micro-lens on the color filter.
 15. The image sensor of claim 14, wherein the image sensor comprises a backside illumination type image sensor, and the color filter is on the bottom surface of the substrate.
 16. An image sensor comprising: a semiconductor substrate including a face; a plurality of semiconductor photodiodes in the semiconductor substrate, at different depths from the face, and being configured to absorb light of different colors; and a semiconductor color adjustment path in the semiconductor substrate that extends between at least two of the semiconductor photodiodes that are at different depths from the face.
 17. The image sensor of claim 16, wherein the semiconductor color adjustment path extends between the at least two of the semiconductor photodiodes at central portions thereof so as to be surrounded by the at least two of the semiconductor photodiodes.
 18. The image sensor of claim 16, wherein the semiconductor color adjustment path extends between the at least two of the semiconductor photodiodes at peripheral portions thereof so as to be only partially surrounded by the at least two of the semiconductor photodiodes.
 19. The image sensor of claim 18 further comprising a transfer transistor that extends into the semiconductor substrate from the face, wherein the semiconductor color adjustment path extends between the at least two of the semiconductor photodiodes at peripheral portions thereof that are furthest away from the transfer transistor.
 20. The image sensor of claim 16 wherein a respective semiconductor photodiode includes regions of first and second different conductivity types that define a semiconductor junction therebetween that extends generally parallel to the face, wherein the semiconductor color adjustment path comprises a pillar of the first conductivity type that extends into the regions of first conductivity type of the semiconductor photodiodes. 